1903] Cushman,— Notes on New England Desmids,— I 223 
Cosmarium pseudobroomei Wolle. Length 50 pw. Diam. 40 y. 
Isthmus r5 pw. No distinct central inflation thus separating it 
from the preceding. Decided difference in this case in size between 
the two. Wolle considers the inflation the only difference. Appar- 
ently new to New England. Wood Lake, New Jersey, is the only 
locality mentioned by Wolle. 
Cosmarium tumidum Lund. Length 29 p. Diam. 25 m. Isth- 
mus 8 u. Maine is the only other of the New England States from 
which this has been previously reported. 
Cosmarium laeve Rab., var. septentrionale Wille. Length 25 p. 
Diam. 18 u. Isthmus 7 u. A little larger than the dimensions given 
by Wolle. He gives no locality in his mention of this form. 
Cosmarium tetrophthalmum (Kg.) Breb. Length 72 yq. Diam. 
58 p. Isthmus 22 p. Wolle simply mentions this species as “ com- 
mon” without giving any definite localities for it. Not reported 
before from New England. 
Cosmarium octhodes Nord. Length 72 u. Diam. 54 u. Isthmus 
18 4. Apices slightly retuse in center. 
Cosmarium pyramidatum Breb. Length 62 p. Diam. 50pm. Isth- 
mus IS p. i 
Cosmarium amoenum Breb. Length 50 p. Diam. 25 p. The 
typical form. 
Cosmarium subcrenatum Hautzsch. Length 38 p. Diam. 25 p. 
Isthmus 14 u. Common. Reported previously from Maine also. 
Cosmarium coelatum Ralfs. Length so u. Diam. 42 p. Isthmus 
12 p. A somewhat aberrant form with three lateral lobules instead 
of one as is usually the case. This variation is indicated in Ralfs’ 
figures but not in his description. The specimen in question agrees 
exactly with one of his original figures (The British Desmidieæ PI. 
xvii, fig. ıc). This species is new to New England. 
Arthrodesmus incus (Ehrb.) Hass. Diam. without spines 20 p. 
Length 15 p. Length of spine r5 p. 
Micrasterias americana (Ehrb.) Kg. Length 145 p. Diam. 97 m. 
Isthmus 3o u. Form slightly narrower than usual. 
Euastrum elegans Kg. Length 32 u. Diam. 22 m. Isthmus 7 p. 
Of the form of the smaller variety from Steep Brook, Massachusetts. 
Staurastrum orbiculare (Ehrb.) Ralfs. Length 22-32 p. Diam. 
22-27 p. Isthmus 7-9 p. Specimens are very common and as the 
measurements indicate they show a considerable variation in size. 
